Crimping apparatus



April 26, 1960 H. H. WEINSTOCK, JR

CRIMPING APPARATUS Filed Oct. 10, 1955 INVENTOR HARRY H. WEINSTOCKJR.

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ATTORNEY CRIMPING APPARATUS Harry H. Weinstock, Jr., Madison, N.J.,assignor to Allied Chemical Corporation, a corporation of New YorkApplication October 10, 1955, Serial No. 539,528

1 Claim. (Cl. 19-66) This invention relates to improved crimpingapparatus of the type wherein a pair of rolls forces filamentarymaterial through the nip of the rolls into a crimping chamber. Byfilamentary material I mean a tow of continuous filaments ora sliver ofstaple filaments.

In apparatus of the above stated sype, especially when operated atspeeds of at least about 150 feet per minute, and especially whenoperated using a fusible thermoplastic such as polycaprolactam, problemsfrequently arise due to lodging and entrapment of filaments beingcrimped, in crevices where the walls of the crimping chamber closelyapproach the circular side surfaces of the feed rolls, e.g. withclearance of about 0.01 inch or less. Problems also arise due to unevenpressures developing in the crimping chamber. The present inventionrepresents a simple and effective means of mitigating these problems.

In accordance with my invention, I provide a restricted passage formedsuitably by a pair of projecting guides, one at each side of theapproach to the nip of the feed rolls in crimping apparatus as abovedescribed. This passage is between about inch and about /2 inch narrowerthan the width of the nip between the said feed rolls; and this passageterminates within the volume lying between the cylindrical feed surfacesof the rolls and the plane tangent to said surfaces at the feed end,generally terminating at a distance in the range between about /2 inchand about 3 inches from the nip of said feed. rolls.

When the entering tow passes through this passage between the guidesinto the nip of the feed rolls, traveling from the entrance end thereofto the terminus, it is held away from the crevices yet substantiallyfills the crimping chamber including the entering end of the chambernear the rolls. Under these circumstance I have found that entrapment offilaments is reduced to a point where it does not seriously interferewith operations; and operating pressures remain substantially uniform asa result of the substantially complete filling of the crimping chamber,especially the filling of the entering end where most of the crimpingaction actually occurs.

Guides located as much as 6 inches from the nip of the rolls areinsuflicient to control filaments at the edges of the moving tow. Uponentering the nip formed by the two rolls of the crimping apparatus,these filaments become disengaged from the main bundle of tow and arecaught in the crevice between the sideplates and the rolls. Tow crimpedunder such conditions is found to have fused and torn edges. Prolongedoperation results in damage to the crimping apparatus.

The accompanying drawing illustrates a typical embodiment of myinvention. In the drawing Fig. 1 is a general perspective view,partially cut away; Fig. 2 is a side view, and Fig. 3 is an end view ofcrimping apparatus fitted with a trapezoidal form of the guides. Fig. 4is a side view and Fig. 5 is an end view of crimping 2,933,771 PatentedApr. 26, 1960 2 apparatus fitted with a bar form of the guides of myinvention.

In all the figures, numeral 1 designates the feed rolls; numeral 2designates the side plates forming the side walls of the crimpingchamber; numeral 3 designates generally the guide of my invention; andnumeral 4 designates a project forming the active guiding surface. Saidprojection may suitably be of generally trapezoidal shape, fittingwithin the curvature of the feed rolls (Fig. 2), or it may berectangular, as in the modification represented in Fig. 4. Numeral 5designates a bolt in a hole for holding the guide on the end of the sideplate 2 or onto spacing shim 8. The holes can be round or, as shown,they can be slotted for easy adjustment of the position of the guide.The guide may also be ad-- justed by a suitable mechanical device ofconventional design, such as a screw. Numerals 6 and 7 designate bladesmeeting the rolls in a knife edge. The two side plates and two bladesform the walls of the crimping chamber. In the drawings a horizontalchamber is shown, but a vertical chamber of similar general constructioncan advantageously be provided likewise with the guide passage of myinvention. The termination of the passage is preferably as close to thenip as is permitted by the height of the projection 4 (i.e. thedimension perpendicular to the axes of th rolls), the radius andresulting periphery of the rolls, and the working clearance betweenguide and the nearest surface of the rolls. This working clearance issuitably about inch. The necessary height of the projection isdetermined by the maximum movement of the tow on the guide surfaceduring operation. For example, if the projection is /2 inch high at theend nearest the nip, and a crimping apparatus with rolls of 2 inch, 6inch, or 12 inch diameter is used, the passage will terminate,respectively, about inch, about 1 /2 inches, or about 1% inches from thenip.

Shorter guides and closer working clearances can be used, but the towmay ride over the guide and the roll surface may be scored by theguides. The practical effect of the guides is lost when the passageterminates at a distance of more than about 3 inches from the nip of thesaid feed rolls.

Two auxiliary width-constricting guides which are positioned about 6inches from the nip of the rolls and which constrict the tow to a widthabout /a inch to inch narrower than the width of the nip between thesaid feed rolls, improve the operation of the guides of my inventionalthough they are practically ineffective in themselves.

The following is an example of operation of crimping apparatus asillustrated in the drawings, employing the guides of my invention.

In repeated tests, a tow or bundle of polycaprolactam nylon filaments of6 denier per filament and total denier of 200,000 was fed from a roll at400 feet per minute through a distance of 10 feet to a crimpingapparatus. Said crimping apparatus was of the horizontal chamber typeshown in the drawings herein, with movable lower blade loaded to opposepassage of the tow through the chamber. It was equipped with nip rolls 2inches wide and 6 inches in diameter. The tow passed through a pair oftow restricting guides 6 inches from the nip, set each about Vs inch toinch narrower than the width of the feed rolls. The filaments on theedges of the tow did not remain with the bundle when entering the nip,but lodged in the crevices between the rolls and sideplates. This causedthe crimped tow product to have fused and torn edges. After continuedoperation under these conditions for about an hour the crimpingapparatus jammed due to fibers lodged in the crevices between the rollsand sidepla'tes. I

In repeated tests, a tow of the same type was crimped in the sameapparatus and under the same conditions except that guides of the typeillustrated in Fig. 4 were used in addition to those already on theapparatus. The acting guiding surfaces were 0.5 inch high by 0.125 inchlong and were set about 0.35 inch narrower than the width of the passagebetween the rolls, leaving a passage of about 1.65 inches. The passageterminated 1.5 inches from the nip of the rolls. The guides kept thefibers on the edge of the tow away from the crevices between the rollsand sideplates. After passing the nip, the tow substantially completelyfilled the crimping chamber. The product was a crimped tow of goodquality, withsoft and well crimped edges. The operation was maintained.continuously for several hours in each test, and at the .end of eachtest there were insignificant quantities of fibers lodged in thecrevices between the rolls and the sideplates.

ln tests like those above but using apparatus of the vertical chambertype along the lines of that shown in Hitt US. Patent 2,311,174 of Feb.16, 1943, results without and with guides in accordance with myinvention were similar, respectively, to the above outlined resultswithout and with my guides.

I claim:

In crimping apparatus whereina pair of feed rolls forces filamentarymaterial through the nip of the rolls n a cr m in mbe sa hambe c m risinsi plates which overlap the circular ends of the rolls with clearance ofnot more than about 0.01 inch, and knife blades which meet the rolls inknife edges parallel to the nip of the rolls with clearance of not morethan about 0.01 inch; the improvement which comprises: a restrictedpassage to the nip of said rolls, said passage being formed by a pair ofprojecting guides, one at each side of the approach to the nip of thefeed rolls; and being between about inch and about /2 inch narrower thanthe width of the nip between said feed rolls, and said passageterminating within the volume lying between the cylindrical feedsurfaces of said rolls and the plane tangent to said surfaces at thefeed end and terminating not more than about 3 inches from the nip of'said feed rolls, whereby the entering tow is held away from thecrevices between the feed rolls and the side plates of the crimpingchamber while substantially filling the crimping chamber.

References Cited in the file of this patent UNITED STATES PATENTS

